PROTEIN-CHANGES IN THE FLOWER BUDS OF JAPANESE PEAR DURING BREAKING OF DORMANCY BY CHILLING OR HIGH-TEMPERATURE TREATMENT

The dormancy of Japanese pear (Pyrus pyrifolia Nakai) floral buds was broken by prolonged chilling or short-term high-temperature treatment (45 degrees C for 4 hours). Changes in the protein profiles of the flo ral buds were studied using two-dimensional electrophoretic analysis ( 2-DE), The quantities of nine cold-induced proteins (CIPs) increased i n the floral buds with increases in chill unit (CU) value, but did not change rapidly when bud dormancy was near completion. When dormancy o f floral buds was broken by high-temperature treatment, nine heat-shoc k proteins (HSPs) accumulated. These HSPs were distinct from the CIPs, The isoelectric point of the 19-kDa CIP shifted to the basic side by high-temperature treatment as well as by chilling. These results sugge st that the 19-kDa protein may be a usable marker to measure the degre e of bud dormancy in Japanese pear.